A circuit board is connected to a connector including a connection port and contact portions located at upper and lower positions of the connection port. The contact portions face each other in the vertical direction, and each contact portion is connected electrically to the opposite contact portion. The circuit board includes a base substrate, a first wiring layer, and a second wiring layer. First terminals connected to the first wiring layer are provided on one principal surface of the base substrate, and second terminals connected to the second wiring layer are provided on the other principal surface. The first terminals and the second terminals come into contact with the contact portions and are arranged so as not to overlap each other in the vertical direction.